Automated identification of goods and other articles has become commonplace. Radio frequency identification (RFID) tags may be used to track the shipment and inventory of goods. In the coming years, RFID tags may be found on goods offered for sale at a large number of retailers. RFID tags may also be used in other applications, including electronic toll collection for vehicles.
Other techniques for automated identification of goods or other articles may utilize bar codes. However, RFID and bar code technologies may suffer from various shortcomings, including limited range and/or excess expense. For example, bar code scanning may function properly from a maximum distance of several feet, and typical bar code implementations may require that the bar code be scanned from a maximum distance of only several inches. Similarly, passive RFID implementations may have effective ranges of only a few feet. Active RFID technologies may provide increased range, but at a significant increase in cost due in part to the active circuitry of the RFID tag, including power supplies that may have limited life spans.